Background-Recent studies have suggested that endogenous erythropoietin (Epo) plays an important role in the mobilization of bone marrow-derived endothelial progenitor cells (EPCs). However, it remains to be elucidated whether the Epo system exerts protective effects on pulmonary hypertension (PH), a fatal disorder encountered in cardiovascular medicine. Methods and Results-A mouse model of hypoxia-induced PH was used for study. We evaluated right ventricular systolic pressure, right ventricular hypertrophy, and pulmonary vascular remodeling in mice lacking the Epo receptor (EpoR) in nonerythroid lineages (EpoR Ϫ/Ϫ rescued mice) after 3 weeks of exposure to hypoxia. Those mice lack EpoR in the cardiovascular system but not in the hematopoietic system. The development of PH and pulmonary vascular remodeling were accelerated in EpoR Ϫ/Ϫ rescued mice compared with wild-type mice. The mobilization of EPCs and their recruitment to the pulmonary endothelium were significantly impaired in EpoR Ϫ/Ϫ rescued mice. By contrast, reconstitution of the bone marrow with wild-type bone marrow cells ameliorated PH in the EpoR Ϫ/Ϫ rescued mice. Hypoxia enhanced the expression of EpoR on pulmonary endothelial cells in wild-type but not EpoR Ϫ/Ϫ rescued mice. Finally, hypoxia activated endothelial nitric oxide synthase in the lungs in wild-type mice but not in EpoR Ϫ/Ϫ rescued mice. Conclusions-These results indicate that the endogenous Epo/EpoR system plays an important role in the recruitment of EPCs and prevents the development of PH during chronic hypoxia in mice in vivo, suggesting the therapeutic importance of the system for the treatment of PH.

InGaN-based light-emitting diodes (LEDs) have been widely accepted as highly efficient light sources capable of replacing incandescent bulbs. However, applications of InGaN LEDs are limited to small devices because their fabrication process involves expensive epitaxial growth of InGaN by metalorganic vapor phase epitaxy on single-crystal wafers. If we can utilize a low-cost epitaxial growth process, such as sputtering on large-area substrates, we can fabricate large-area InGaN light-emitting displays. Here, we report the growth of GaN (0001) and InGaN (0001) films on amorphous SiO2 by pulsed sputtering deposition. We found that using multilayer graphene buffer layers allows the growth of highly c-axis-oriented GaN films even on amorphous substrates. We fabricated red, green, and blue InGaN LEDs and confirmed their successful operation. This successful fabrication of full-color InGaN LEDs on amorphous substrates by sputtering indicates that the technique is quite promising for future large-area light-emitting displays on amorphous substrates.

These data suggest that a high endogenous EPO level can predict a smaller infarct size in patients with acute MI subjected to successful primary PCI. This might be attributed to the potentially protective effect of endogenous EPO against ischemia-reperfusion injury in humans.

We have grown GaN on atomically flat ZnO (000-1) substrates at room temperature with pulsed laser deposition (PLD). We have found that atomically flat surfaces of ZnO (000-1) substrates with a clear step and terrace structure have been obtained by annealing in a box made of ceramic ZnO. We have also found that GaN grows epitaxially even at room temperature on the step and terrace ZnO surface. Reflection high energy electron diffraction (RHEED) observations have revealed that the GaN film grows in the layer by layer mode from the early stage of the film growth. X-ray reflectivity measurements have revealed that the heterointerface between GaN and ZnO is quite abrupt and its roughness is less than 0.5 nm.